Thread-severing mechanism



Dec. 4, 1934. v o. KLEINSCHMIT 1,983,465

THREAD SEVERING MECHANI SM Filed Oct. 18. 19:52 a SheetS -Sheet 1 W i W Dec. 4, 1934. o. KLEINSCHMIT 1,983,465

THREAD SEVERING MECHANISM Filed 001,. 18, 1932 3 Sheets-Sheet 2 1934- o. KLEINSCHMIT 1,983,455

THREAD SEVERTNG MECHANI SM Filed Oct. 18, 1932 3 Sheets-Sheet 5 Patented Dec. 4, 1934 OFFiQ THREAD-SEVERING MECHANISM Oscar Kleinschmit, Leipzig-Plagwitz, Germany,

assignor to Gebruder Brehmer, Leipzig-Plagwitz, Germany, a limited partnership of Germany Application October 18,

1932, Serial No. 638,417

In Germany October 29, 1931 18 Claims.

The present invention relates to mechanism for mechanically severing the connecting threads between the adjacent sections or books of a stitched book-pad produced in a book-stitching or book-binding machine.

According to the present invention means for mechanically severing the connecting threads between the adjacent books or sections of a stitched book-pad is provided whereby the requisite thread is severed by a severing device in a contact which is achieved independently of the movement of the book-pad.

A modification of this structure resides in the provision of means for severing a single thread or the limbs or a limb of a looped thread extendfrom the stitching needles to the last formed stitch applied to the book-pad.

To carry into effect this invention use may be made of a movable thread separator or selector which may with advantage be provided with a hook which is inserted in a thread chain loop,

preferably suspended from a looping needle, to

engage a limb thereof or which is caused to engage the thread extending from the stitched book to the sewing needle.

The thread separator, during the movement imparted thereto, engages the thread to be severed and exerts pressure thereon so that the thread is held tensioned in the hook.

The portion of the hook contacting with the thread may be formed as a knife edge or serve to carry a severing device which is utilized to sever the tensioned thread held by the said hook.

Alternatively a separate thread-severing device stationary or movable may be associated with the movable hook so that the thread held thereby is brought into engagement with the severing device.

In the formation of an idle chain-loop stitch the looped thread is subjected to strong tension in the upward movement when: drawn through the preceding loop, and the insertion of the separator in the chain loop during this movement is dilficult since the tensioned threads are not readily parted to permit the entry of the separator. For this reason it is advantageous to cause the entry of the separator to take place as the chain loop has been drawn up to the highest position of the chain-looping needle for the reason that the moment is opportune to attain a slackening of the threads, enabling therefore the severance to be effected without risk as will be appreciated by those skilled in the art.

The separator may be provided with a lateral projecting'hook or it may be upright either in the upward or downward sense, in which case, however, it should preferably perform a quarter of a revolution about the axis of its shaft in order to enable the hook to become effective. In this case when applied to a chain-loop stitch the spreading of the thread loop takes place after the insertion of the separator into the loop.

Alternatively the method of this invention may be carried into effect by means of a severing device which is brought directly to the thread to be severed. Such severing device may be utilized to sever the thread depending from the stitching needles during the formation of the final stitch of each book or section of the pad or after the completion thereof. The control of the thread severing devices above referred to may be effected by hand or by adjustable automatic controlling means of any suitable type.

In order that the invention may more clearly be understood two practical embodiments of the mechanism for carrying the invention into effect will now be described by way of example and with reference to the accompanying drawings in which:

Fig. 1 is a part sectional, elevational view of one constructional form of the thread severing device above referred to, shown associated with the chain-loop thread stitching needles of a book-stitching machine of the usual oscillating sheet carrier type.

Fig. 2 is a fragmentary elevational view of the arrangement looking in the direction of the arrow A (Fig. l) and showing the formation of an idle stitch subsequent to the stitching of the final section of a book.

Fig. 3 is a top plan view thereof.

Fig. 4 shows a detail view of a portion of a book-pad bound with chain loop thread stitch- Fig. 5 is an elevational View similar to Fig. 1 but showing a modified thread severing device.

Fig. 6 is a view taken at right angles to Fig. 5,

and

Fig. '7 is a plan view thereof.

Referring to Figs. 1, 2 and 3 it will be seen that-the thread stitching mechanism indicated includes a slotted oscillatory sheet carrier or stitching saddle 10 which moves beneath a needle guide or bar 11 the latter being firmly secured transversely of the machine in supporting brackets (not shown). Thread stitching needles comprising sewing needles 12 and looping needles 13, an operative pair of which are shown in the drawings, are mounted above the guide bar 11 and move therethrough and through the slot of the carrier saddle 10 to co-operate in known manner with a reciprocating thread gripper 14 which is located beneath the stitching saddle 10 in order to insert chain loop thread stitches into the signature or book section S straddling the saddle 10. A pad B of continuously stitched books as shown in Fig. 4 is thus produced. It is advantageous although not essential to form an idle or looking stitch between the last section of one completed book and the first section of the adjacent book and it is assumed in the following description that such idle stitches are utilized so that normally the adjacent books of the pad are connected by a double thread b as shown in Fig. t. Alternatively if an idle stitch is not interposed between the adjacent books the connecting threads pass directly from the final section of one book to the first section of the adjacent book and must be severed at the point marked 22 in Fig. l.

The guide bar 11 carries on its forward edge a series of conveniently adjustable and removable guiding supports 15 in which carrier members 16 are slidably mounted. The latter members each carry a substantially horizontal thread severing member 17 which extends longitudinally of the book-pad and above thereof and is adapted to pass through suitable apertures provided in the flange 11a of the guide bar 11 so as to align with the sewing needles 12 and looping needles 13. In the arrangement shown the severing members 17 pass only through those apertures aligned with the looping needles 13 but if desired the severing members may also be provided to engage the threads held by the sewing needles. The free extremity of each cutting member 17 is wedgeshaped and is provided with an oblique cutting edge 17a. The edge of the cutting member is set in such manner as to engage and sever one limb of the corresponding thread loop when moved.

The reciprocatory movement of the thread severing members is brought about in this arrangement by cam actuated mechanism as indicated in Figs. 1 and 2 and more particularly described in British Patent No. 362,863 to Gebriider Brehmer while when idle stitches are interposed between the books of the book-pad the timing of the cam actuated mechanism may be achieved by the controlling means also described in the above mentioned patent.

In the operation of this thread severing device each signature S is placed on the stitching saddle 10 which conveys it to the stitching needles 12 and 13. The sewing needle 12 penetrates the fold of the signature and draws the thread therethrough and is then withdrawn a certain dis tance to form a thread loop which is engaged by the thread gripper 14 and drawn towards the downwardly descending hook needle 13 which engages and withdraws the loop through the signature to the outside thereof and interengages it with the preceding loop. This stitching operation is repeated with each signature until the final signature of the book is stitched whereupon the saddle is permitted to perform an idle feeding movement so that the stitching needles form an idle stitch.

By means of the timing control mechanism described in the patent referred to the cam actuated mechanism is permitted to function during or immediately after the formation of the idle stitch and the aligned severing member 17 is caused to move forward to engage a limb of the looped thread held by the looping needle 13 and extending to the book-pad. In this movement the cutting edge 17a of the member 17 severs the thread limb and in accordance with the rotation of the actuating cam the member 17 is immediately withdrawn to the inoperative position to permit the continuance of the book-stitching operations.

The thread is severed as shown in Fig. 4 and since in practice the thread of the severed loop is tightly held by the preceding loop 0 the end of the severed thread should not become unravelled from the preceding stitch. If, however, it is considered that this may occur it is possible readily to associate a thread braking or retaining device with the severing blade, the retaining device being actuated, if necessary, by the operative movement of the latter so as to retain the severed thread end at the side of the book or in the interior of the signature when an idle stitch is not used. The use of a thread retaining device of this nature is advantageous if the chain loop is severed immediately above the back fold of the signature and severed in that portion of the thread leading directly to the sewing needle.

Instead of bringing the severing member 17 against one limb of the chain loop so that the thread is severed from outside, the severing member may be caused to pass between and separate the limbs of the thread loop; one of which limbs would then contact upon its inner side with the cutting edge 170..

If, instead of the chain loops, the thread extending from the sewing needle is to be severed this operation is effected in a similar manner. In this case the severing member 17 is timed to contact with and sever the thread at the moment when the sewing needle is at the uppermost point of its movement so that the stretch of thread extending from the eye of the sewing needle to the level of the severing edge of the member 17 is of su-fiicient length toprevent the severed end thereof from sliding out of the needle eye during the formation of the next stitch.

Referring to Figs. 5, 6 and 7, in the alternative embodiment of the mechanism for carrying the method of this invention into effect the front face of the flange 11a of the bar 11 serves to support a guide rod or series of such rods 20 which extends or extend longitudinally of the book-pad and above thereof. Each guide rod 20 has a collar or carrier slidably mounted thereon and to which in each case is attached in a readily attachable and adjustable manner a thread selector or shaft 22 provided with a hook at its free extremity which latter is aligned with a looping needle or sewing needle as the case may be. The rear face of the guide bar 11 serves to support thread severing knives 23 one of which is associated with each thread selector 22 and positioned immediately below the latter so as to extend transversely thereof as shown in the drawings.

Reciprocatory movement is imparted to the hooked thread selector by mechanism which may be actuated, timed and, if desired, controlled in a manner similar to that referred toin reference to the first described embodiment. By the means utilized for this purpose the hooked member is advanced when desired towards the last formed chain loop thread stitch as the latter hangs on the hook of the looping needle 13 and the tapered nose of the hook passes therethrough thus separating the limbs of the thread loop. In the arrangement shown the wedge shaped hooked nose of the thread selector is positioned in the horizontal plane so that in passing through the thread loop the latter is distended to permit the passage of the hook and finally the thread limb to be severed lodges behind the shoulder 22a of the hooked selector. In actual practice to facilitate the passage of the hooked nose of the selector through the thread loop the tension of the latter preferably is slackened by a suitable movement of the stitching needle. In the return movement of the reciprocating thread selector the thread limb lodging behind the hook shoulder 22a is drawn against the cuttingedge 23a of the knife 23 and thus severed. In this rearward motion the tension of the thread may again be relaxed to prevent undue strain upon the stitches.

In a modified arrangement of this severing device the knife blade 23 could be dispensed with and the rear edge or shoulder 22a sharpened to a knife-edge to effect the severance of the thread engaged thereby during the return movement of, in this case, the combined thread selector and severing member.

Instead of entering the loop of the thread to be severed the hooked extremity of the member 22 may be caused to approach the loop and bear from the outside upon one of the thread limbs of the looping thus to engage and, if desired, sever the thread.

As above mentioned the selector member 22 may be provided with a hook which normally is in the vertical plane thus facilitating the passage thereof through the thread loop and in this case the selector member, subsequent to the passage of the hook beyond the thread to be engaged, would be rotated to position the shoulder of the hook transverse to the thread limb which it is desired to engage thereby.

It will be obvious from the above description that if desired a single thread leading from the sewing needle to the book-pad can with equal facility be severed with the aid of the movable hooked thread selector member.

To prevent a flinging away or unravelling of the severed thread at the moment of severance a thread retaining device operated in known manner may be associated with the operative movement of the member 22 or care may be taken by properly regulating the thread tension to obtain a suitable tightening or locking of the preceding stitches prior to the severance of the thread.

When an idle stitch is not interposed between the adjacent books the actuation of the thread severing device may be controlled by means of known counting mechanism associated with the stitching machine or, of course, the mechanism may be controlled manually, e. g., by an attendant releasing a lever or the like during the manipulation of the final signature of each completed book. I

n It will be understood that while the severance of a thread or threads of a single stitch has been more specifically described herein the thread severing device may be duplicated and synchronized so as to sever simultaneously or consecutively a plurality of such stitches.

I claim:

1. Means for mechanically severing the threads serving to interconnect the books of a continuously stitched moving book-pad, including means for holding extended a thread leading from a formed stitch, a member adapted to engage the extended thread, and means for imparting movement to said thread engaging member so that said thread is severed independently of the movement of the stitched book-pad.

2. Means for mechanically severing the threads serving to interconnect the books of a continuously stitched moving book-pad, including means for holding a thread extended from a formed stitch, a thread-severing member adapted to engage said extended thread, and means for imparting reciprocatory linear movement to said thread-severing member so that it advances to sever said thread and is retracted to its initial position after the severance of the thread.

3. Means for mechanically severing the threads serving to interconnect the books of a continuously stitched moving book-pad, including means for holding a thread-loop extended from a formed stitch, a thread-severing member hav ing a cutting-edge shaped to penetrate between the limbs of the thread loop, and means for imparting movement to said severing member so that the latter passes between the limbs of said thread loop and severs at least one of said thread limbs.

4. Means for mechanically severing the threads serving to interconnect the books of a continuously stitched moving book-pad, including means for holding a thread-loop extended from a formed stitch, a thread-severing member having its cutting edge forming one side of a tapered nose, and means for imparting movement to said thread-severing member so that its nose passes between the limbs of the thread-loop to contact said cutting edge with one limb of said loop.

5. Means for mechanically severing the threads serving to interconnect the books of a continuously stitched moving book-pad, including a movable thread-engaging member, a stationary thread-severing member, and means for imparting movement to said thread-engaging member so that the latter engages the thread to be severed and draws it into contact with said thread-severing member.

6. Means for mechanically severing the threads serving to interconnect the books ofa continuously stitched moving book-pad, including a movable thread-engaging member having a hooked nose and a stationary thread-severing member provided with a cutting edge and means for imparting reciprocatory movement tosaid thread-engaging member so that the latter engages the thread to be severed and draws it into contact with the cutting edge of said thread-severing member.

7. Means for mechanically severing the threads serving to interconnect the books of a continuously stitched moving book-pad, including a substantially horizontal thread-severing member having a hooked extremity sharpened to a cutting edge on its inner side, and means for imparting reciprocatory movement to said thread-severing member so that the thread is engaged by the hooked extremity of said threadsevering member and severed in the reciprocatory duce a continuously stitched book-pad, a threadsevering device which includes a substantially horizontal holder adapted to move longitudinally of the book-pad, a thread-engaging member extending from said holder and having its free extremity shaped to engage the thread to be severed, and means for imparting reciprocatory movement to said holder and said thread engaging member so that said thread is engaged by said member and severed.

10. In a book-stitching machine adapted to produce a continuously stitched book-pad, threadsevering means comprising, in combination, means for holding a looped thread extended from the book pad, a holder adapted to move longitudinally of said book-pad, a thread-engaging member mounted in said holder and having its free extremity formed as a hook, a thread-severing member and means for imparting movement to said hooked member so that the latter engages one limb of the thread-loop and urges it into contact with said severing member.

11. In a book-stitching machine adapted to produce a continuously stitched book-pad, threadhandling means comprising, in combination, a thread-looping needle adapted to hold a looped thread extended from the book-pad, a threadsevering member movably mounted above said book-pad and means for imparting movement to said severing member so that the latter contacts with and severs at least one limb of the extended loop.

12. In a book-stitching machine adapted to produce a continuously stitched book-pad, threadhandling means comprising, in combination, a thread sewing needle, a thread-looping needle, a thread severing member mounted above said book-pad, a thread-engaging member mounted above said book-pad, and means for imparting movement to said thread-engaging member so that the latter engages the thread to be severed and urges said thread into contact with said severing device.

13. In a book-stitching machine adapted to produce a continuously stitched book-pad, in combination, a guide support member mounted above the book-pad, a carrier member slidably mounted in said guide support, a thread-severing member secured to said carrier member so as to extend longitudinally of the book-pad, a thread-looping needle adapted to hold a thread loop extended upwardly from said book-pad, and means for imparting reciprocatory movement to said carrier member and said thread-severing member attached thereto so that the latter is advanced to engage and sever at least one limb of said thread loop and is retracted to its initial position after the severance of said thread.

14. In a book-stitching machine adapted to produce a continuously stitched book-pad, in combination, a plurality of guide support mem. bers mounted above the book-pad, carrier members slidably mounted one in each guide support, thread-severing members secured one to each carrier member, said severing members extending longitudinally of the book-pad, thread-looping needles adapted to hold thread loops extended upwardly from the book-pad, and means for imparting reciprooatory movement to said carrier members and said thread-severing members attached thereto so that the latter are advanced to engage and sever at least one limb of each of the said thread loops and retracted to their initial positions after the severance of said threads.

15. The combination claimed in claim 14, in which the thread-severing member has its free end formed as a hooked nose sharpened to a cutting edge on an inner side thereof so as to sever the thread engaged thereby during the reciproca tory movement of said severing member.

16. In a book-stitching machine adapted to produce a continuously stitched book-pad, in combination, a guide support member mounted above the book-pad, a carrier member slidably mounted in said guide support, a thread-engaging member secured to said carrier member so as to extend longitudinally of the book-pad, a threadsevering member positioned in the path of travel of said thread-engaging member, means for holding a looped thread extending upwardly from the book-pad, and means for imparting reciprocatory movement to said carrier member and said thread-engaging member so that the latter is advanced to engage at least one limb of said extended thread loop and then retracted to draw the engaged thread into contact with said severing member.

17. In a book-stitching machine adapted to produce a continuously stitched book-pad, in combination, a plurality of guide support members mounted above the book-pad, carrier members slidably mounted in said guide supports, threadengaging members secured one to each carrier member, said thread-engaging members extending longitudinally of the book-pad, threadsevering members positioned in the path of travel of said thread-engaging members, means for holding looped threads extending upwards from the book-pad, and means for imparting reciprocatory movement to said carrier members and said thread-engaging members carried thereby so that the latter are advanced to engage at least one limb of each extended thread loop and then retracted to draw the engaged thread into contact with said severing members.

18. Means for mechanically severing the threads serving to interconnect the books or" a continuously stitched moving book-pad, including a movable thread-engaging member, a thread-severing member having its cutting edge set transversely of the path of travel of said thread-engaging member, and means for imparting movement to said thread-engaging member so that the latter seizes said thread and draws the latter into engagement with said severing member.

OSCAR KLEINSCHMIT. 

